If you put a <ui:include> tag before a composite component that nests other composite components, you'll get this:
javax.faces.view.facelets.TagException: /resources/lib/useboth.xhtml @19,33 <lib:greet1> Tag Library supports namespace: http://java.sun.com/jsf/composite/lib, but no tag was defined for name: greet1
I've verified the error on a 2.1.8 snapshot and on a 2.2 snapshot. This does not occur on 2.1.7. I'm seeing this in a version taken from a 2.1.8 snapshot in late February. So it was broken some time before March. I'm guessing it might have something to do with
JAVASERVERFACES-2328. But that's just a guess at this point.
I'm attaching a maven project that builds a tiny app to reproduce the problem.